Arrangement for transporting highly dispersed powders, and method of filling and emptying the same

ABSTRACT

A container with a top edge, a bottom edge and a rear side provided with a door, containing an inliner, wherein the inliner comprises at least two layers located one above the other, an inner layer consisting of uncoated, air-permeable fabric and an outer layer being coated so as to be dust-tight and to provide a moisture barrier, these layers being connected to one another by a special seam such that dust-free venting of the receptacle is possible only through this seam, the inliner being fastened in a reversible manner in the container and having at least one filling opening and an emptying opening.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a container for transporting highly dispersedpowders and to a method of filling and emptying the same.

2. Background Art

Handling pourable materials of extremely low bulk density gives rise toproblems in various respects. Both the manufacturers and the end usersare faced with the fact that such materials swirl up dust even in thecase of extremely low levels of air convection. The creation of dustmust be avoided in order to protect staff who handle the materialsagainst potential health risks caused by breathing in the dust.Furthermore, the low bulk density causes increased transportation costsbecause the ratio of receptacle weight to filling weight is high and acorrespondingly large amount of packaging material is required.

EP-A 0 773 159 (U.S. Pat. No. 5,682,929) discloses a method of fillingand emptying a container with pourable material of low bulk density,multiple times. The fabric containers disclosed therein, the so-called“Big Bag” or “Super Bag,” have a filling capacity of 90 to 350 kg. Thefabric container consists of a flexible, air-permeable fabric,preferably a plastic fabric with one or more layers and with at leastone access opening. These fabric containers are filled by means ofvacuum-filling systems. In this case, the fabric container is subjectedto the action of negative pressure and the material is sucked throughthe open access opening into the fabric container until a predeterminedfilling weight has been reached. The gas here is distributed over theentire surface of the fabric container. During filling, the material iscompacted in a reversible manner without its structure being destroyedin the process, in a manner similar to being filled into sacks.

The abovementioned receptacles, however, have a series of disadvantages,which are partially eliminated in the large flexible receptaclesdisclosed in EP 0982238 A. These flexible receptacles are characterizedin that they comprise at least two layers located one above the other,an inner layer consisting of an uncoated, air-permeable fabric and anouter layer being coated so as to be dust-tight and to provide amoisture barrier, these layers being connected to one another by aspecial seam such that venting of the receptacle is possible onlythrough this seam.

These large flexible receptacles are indeed impermeable to moisture andallow high levels of stability and dust-tightness, but they are limitedin terms of the filling quantity. It is also desirable for largereceptacles to be configured such that filling and emptying can beaccelerated and precisely apportioned.

SUMMARY OF THE INVENTION

Disadvantages of prior art contained are improved upon by a containerwith a top edge, a bottom edge and a rear side provided with a door, thecontainer containing an inliner, wherein the inliner comprises at leasttwo layers located one above the other, an inner layer consisting ofuncoated, air-permeable fabric and an outer layer being coated so as tobe dust-tight and to provide a moisture barrier, and these layers beingconnected to one another by a special seam such that dust-free ventingof the receptacle is possible only through this seam, the inliner beingfastened in a reversible manner in the container and having at least onefilling opening and an emptying opening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of an inliner of the presentinvention;

FIG. 2 illustrates one embodiment of a filling grid for the rear dooropening of the container;

FIG. 3 illustrates one mode of filling the container with a fine powder;and

FIG. 4 illustrates a discharge device useful in one embodiment of theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The container is preferably a standard transporting container which iscommonly used throughout the world. The inliner corresponds, in terms ofconstruction, to the construction of the large receptacle which isdescribed in EP 0982238 A, although the inliner is configured such thatit completely fills the interior of a standard container. The inliner ispreferably configured such that the seams of the inliner which aredescribed in EP 0982238 A are located in the longitudinal direction ofthe container, on the top and bottom edges of the latter. The fillingopening of the inliner is preferably in the form of a filling connectorcomprising a fabric hose which is fixed to the inliner. The fabric hosepreferably consists of the same material as the inliner. The fillingconnector preferably has a length of less than 100 cm and preferably adiameter of between 5 and 40 cm. The filling opening and the emptyingopening are preferably located one beside the other on the bottom edgeof the rear side of the container. The emptying opening preferablycorresponds, in terms of shape and size, to the filling opening.

In order for the inliner to be suspended in a dimensionally stablemanner in the container during filling and emptying, the inliner ispreferably fastened in a reversible manner, by means of a plurality offixing loops, on the eyelets and fastening crosspieces in the interiorof the container (FIG. 1). There are preferably 1 to 10 fixing loops oneach longitudinal edge of the inliner. Each fixing loop is preferablyfastened on the inliner by an overlooked seam. Since standard containershave different fastening points, usually eyelets or crosspieces, in theinterior, but the inliner has standard fixed loops, flexibility forfitting in the fixing loops of the inliner is preferably achieved inthat a plurality of eyelets (crosspieces) of the container are connectedto a strip and this strip can run through the fixing loops.

By virtue of the inliner being vented over its entire inner surface,reversible compaction of the high air content solids is made possibleduring the filling operation, this compaction not changing the productproperties. It is only by this means that a high degree of filling ofthe container/inliner can be achieved.

The invention also relates to a method of filling a container accordingto the invention. The filling method is defined in that, in thecontainer according to the invention, the inliner is filled withcontents via the filling opening, by means of dense-stream conveying,until a predetermined filling weight has been reached, the dense-streamconveying system is removed and the filling opening is then closed.

During filling, use is made of dense-stream conveying which applies thenecessary compacting pressure, compaction preferably taking place bymeans of diaphragm pumps.

In contrast to the method which is known from EP-A 0 773 159, theinvention does not use negative pressure; rather, the product isintroduced into the inliner with pressure, in which case the dissipationof pressure (air) does not take place via a separate opening; rather,the inliner is vented preferably over the entire surface of the innerfabric layer of the inliner into an intermediate region between theinner fabric layer and outer fabric layer, and the rest of the ventingoperation in the outward direction takes place from this intermediateregion via the seams of the inliner.

During filling of the container, a filling grid (FIG. 2) is preferablyinserted into the rear-side door opening of the container. This avoidsthe inliner bulging out there during filling and ensures that the doorsof the container are easily closed once the inliner has been filled. Itis preferable, for this purpose, for the filling grid (1) to be fitted,in the first instance, from above into the ISO blocks (3) of thecontainer (2). Two side frames (4) with fastening hooks (5) are insertedon the left and right into the filling grid (1) hanging on the container(2). The two fastening hooks (5) are then fitted into the ISO blocks (3)at the bottom left and right and pushed into the ISO blocks until theycome to a stop. The entire filling-grid frame is fixed to the container.This can take place, for example, by means of two hand wheels (6).

FIG. 3 shows, by way of example, the operation of filling the inliner inthe container. The filling connector (7) of the conveying unit isconnected to a feed vessel containing the high air content solids, andis pushed into the filling hose (8) to the extent where it projectsapproximately 10 cm into the inliner (9). The filling connector (7) isconnected in a dust-tight manner to the filling hose (8) and thus to thefilling opening of the inliner. Filling takes place via the fillingconnector, the contents being conveyed into the filling connector bymeans of a pressurized conveying system, preferably by means of acontrollable diaphragm pump. In addition, fluidizing air is introducedinto the filling connector (7) to the extent where the flowability ofthe contents is maintained without, at the same time, excessivequantities of air being brought into the inliner.

If the desired (i.e. usually maximum) filling weight has been achieved,the filling connector is uncoupled and the filling opening of theinliner is closed. The end point of the filling operation is determined,for example, via a pressure sensor, the increase in pressure determiningthe end point of the filling operation and the latter being terminatedautomatically. Quantities below the maximum filling weight may bedetermined, for example, via the filling period or via a platformweigher on which the entire unit is standing.

The invention also relates to a method of emptying a filled containeraccording to the invention. This method is defined in that the emptyingopening of the inliner of the filled container is connected to adischarge arrangement and a suction device and opened and the contentsare sucked out of the inliner with the aid of the suction device. Thecontainer is preferably emptied by means of a discharge device (FIG. 4),which can be fitted to the standard container.

The discharge unit is preferably constructed such that it can be fixedin the ISO blocks of the container. It preferably comprises a preferablyconical emptying tube (11) and a supporting cage (12). The emptying tube(11) is pushed into the emptying opening (14) of the inliner andconnected in a dust-tight manner thereto for dust-free emptyingpurposes. The supporting cage (12) can be pushed in a variable mannerinto the emptying opening (14) of the inliner.

The supporting cage (12) ensures, during emptying, that, in the case ofa suction-action conveying system, the emptying hose of the inliner isnot compressed. The supporting cage preferably contains fluidizingopenings through which it is possible to blow in preferably air or inertgases for loosening the material in the region of the emptying openingof the inliner (DL), in order to re-establish the flowability of thesolids for the emptying operation to the necessary extent.

During emptying, use is preferably made of a discharge device with apressure-pulse generator (13), preferably with a control unit, thepressure-pulse generator, during emptying, ensuring friction-freeproduct discharge of the material by the flowability of the materialbeing improved via pressure pulses. The control unit is, for example, apneumatic or electric device by means of which the frequency of thedischarge-assisting pressure pulses can be adjusted, i.e. set torequirements, e.g. initiating the compressed-air gun every 5 or 10minutes.

In order to render the material capable of flowing, it is preferred forthe filled container to be moved into an oblique position,preferably >30° from the horizontal.

The container and method according to the present invention aresuitable, in particular, for transporting highly dispersed silicic acid.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A container with a top edge, a bottom edge and a rear side providedwith a door, containing an inliner, wherein the inliner comprises atleast two layers located one above the other, an inner layer ofuncoated, air-permeable fabric, and an outer layer being coated so as tobe dust-tight and to provide a moisture barrier, these layers beingconnected to one another by a seam such that dust-free venting of thereceptacle is possible only through this seam, the inliner beingfastened in a reversible manner in the container and having at least onefilling opening and at least one emptying opening.
 2. The container ofclaim 1, wherein the filling opening and the emptying opening arelocated adjacent each other on the bottom edge of the rear side of thecontainer.
 3. The container of claim 1, wherein the inliner isconfigured such that the seams of the inliner are located in thelongitudinal direction of the container, on the top and bottom edges ofthe container.
 4. The container of claim 1, wherein the filling openingof the inliner is in the form of a filling connector comprising a fabrichose which is fixed to the inliner.
 5. The container of claim 1, whereinthe emptying opening is similar, in terms of shape and size, to thefilling opening.
 6. A method of filling and emptying a container ofclaim 1, wherein, the inliner is filled with contents via the fillingopening by means of dense-stream conveying until a predetermined fillingweight has been reached, the dense-stream conveying system is removed,and the filling opening is closed.
 7. The method of claim 6, whereinfilling takes place by means of a diaphragm pump.
 8. The method of claim6, wherein, a filling grid is inserted into the rear-side door openingof the container.
 9. A method of emptying a filled container of claim 1,wherein the emptying opening of the inliner of the filled container isconnected to a discharge arrangement and a suction device and opened,and the contents are sucked out of the inliner with the aid of thesuction device.
 10. The method of claim 9, wherein the discharge devicecomprises a pressure-pulse generator which ensures friction-free productdischarge of the material during emptying by the flowability of thematerial being increased via pressure pulses.
 11. The method of claim 9,wherein the discharge device is fitted to the container.
 12. The methodof claim 9, wherein the container is located in an oblique positionduring emptying.
 13. The method of claim 12, wherein said obliqueposition is greater than 30° from horizontal.